blue devil in WordNet English dictionary

1. the sodium salt of amobarbital that is used as a barbiturate; used as a sedative and a hypnotic
   amobarbital sodium  blue  blue angel  blue devil  Amytal 
   
2. a coarse prickly European weed with spikes of blue flowers; naturalized in United States
   blueweed  blue devil  blue thistle  viper's bugloss  Echium vulgare